UNIFIED THEORY OF STIMULATED RAMAN-SCATTERING AND 2-PLASMON DECAY IN INHOMOGENEOUS PLASMAS - HIGH-FREQUENCY HYBRID INSTABILITY

The theories of stimulated Raman scattering (SRS) and two-plasmon deca y (2 omega(pe)) in inhomogeneous plasmas have been unified by adopting a powerful new variational approach. We call this technique the minim um pump strength principle (MPSP), and the unified process, the high f requency hybrid instability (HFHI). The growth rate and frequency shif t of the most unstable mode of HFHI are shown to match smoothly onto t he two known limiting cases: 2 omega(pe) at large k, and SRS backscatt ering as k goes to zero. The effectiveness of this method has allowed the generalization of the density inhomogeneity treated from a constan t gradient to any positive-integer power law. Potential experimental s ignatures of HFHI modes are described.